Shelby, the senior Republican on the Banking Committee, chaired by Dodd, told CNBC that the bill will need more than one or two Republican votes to win passage in the Senate.
"I have no doubt that Democrats can move this out of the committee," Shelby said. "The question is, Can they move it off the floor? I say they won't be able to [without] critical mass; that is, a lot of Republican help."
Dodd (D-Conn.) is set to unveil his package of regulatory changes later on Monday after deciding to release legislation without any GOP support.
Dodd has scheduled a markup for the week of March 22 and is trying to pass the legislation through the banking panel before the Easter recess.